Automatic control device for the pneumatic cleaning of coal



April 21, 1936. M D. SPINETTA ATIC CONTROL DEVICE FOR THE PNEUMATIC CLEANING OF GOAL Filed March 9, 1934 5 Sheets-Sheet 1 AUTOM Tigl U: Y m r /rfafi DOM/N/QO/i .i l/viTr/l April 21, 936. D. SPlNETTA TOMATIC CONTROL DEVICE FOR THE PNEUMATIC CLEANING'OF COAL Filed March 9, 1934 5 Sheets-Sheet 2 m g-aw April 1936. D. SPINETTA AUTOMATIC CONTROL DEVICE FOR THE PNEUMATIC CLEANING OF COAL Filed March 9, 1954 5 Sheets-Sheet 5 M/I/E/VTOE. DOM/N/ql/E S /METr/J Patented Apr. 21, 1936 UNITED STATES AUTOMATIC CONTROL'DEVICE FOR THE PNEUMATIC CLEANING OF COAL Dominique Spinetta, Nogent-sur-Marne, France,

assignor to Preparation Industrielle des Combustibles, Nogent-sur-Marne, France Application March 9,

1934, Serial No. 714,847

In France March 10, 1933 12 Claims.

For some years past dry tables have been uti-- lized for cleaning coal, said tables substantially comprising a vibrating box whereon the coal travels due to the vibration. The-coal is cleaned by a current of air blown by a blower under the box which has a perforatedbottom.

In some tables the various products are ejected along a lateral edge, in others at the front of the table where the products arrive in superposed layers. It is necessary in all cases to adjust the blades or other devices efiecting the separation of the various products by hand ac cording to variations in the feed. Obviously, such tables may treat products of any type. In the following the cleaning of coal is referred to as an example, but merely as a matter of convenience of description.

The existing devices suffer from the following defects:-Since the adjustment is effected manially it is intermittent and subject to human errors, moreover it always lags behind the cause which makes the adjustment necessary.

The present invention has for its object to provide a device whereby the automatic control of the various ejecting operations may be accomplished in accordance with variations as to quantity and quality in the feed, with a View to rendering the composition of cleaned coal or cleaned coal and shale separated by the table is uniform as possible.

The device substantially comprises a weighing instrument operating continuously or intermittently and influencing the control of the table according to the density of one of the products obtained, or simultaneously according to various products obtained, e. g. cleaned coal and shale, or to increase the sensitivity according to the density of the heaviest layer of coal or the lightest layer of shale, the composition whereof is most eiiected by variations in their contents of graded products.

The weighing instrument will automatically weigh either in a continuous manner a constant volume charge, or in an alternate manner a constant volume of the products on the density of which the control is to be based, and will displace the blades eiiecting the separation of the various products graded by the table either directly or through a servo motor in the required direction according to its position, which varies solely according to the density of the weighed product.

The advantages of the automatic control device are as followsz--exclusion of manual labour in the control, immediate displacement of the blades for separating the various products, ac-

curate control with resultant uniform products irrespective of variations in the feed or in the composition of the crude coal or other products fed to the table,

In the attached drawings one embodiment of the automatic control device according to the invention is illustrated by way of example.

Fig. 1 is a side elevation of the device embodying a continuous weighing apparatus.

Fig. l diagrammatically illustrates an audible acoustic warning device.

Fig. 2 is a front elevation of the same device.

Fig. 3 is a side elevation of a device comprising an intermittent weighing apparatus operating at very short and constant intervals.

Fig. 4 is a plan view of a detail of the weighing apparatus.

Figs. 5 and 6 are detail views of the intermittent weighing device shown in Figs. 3 and 4.

Fig. 7 is a cross-sectional view taken on the line 1-1 of Fig. 6.

The coal to be graded is treated on the pneumatic cleaning table I. To simplify the description only the control of the ejection of cleaned coal, based on the density of the heaviest layer of these products, will be referred to.

The coal is graded into shale, mixtures to be recleaned and cleaned coal which rests on the perforated bottom 2 and is ejected laterally over the cascading edge or ramp 3, the density of the products ejected over said ramp 3 increasing from A towards B.

There are in existence tables wherein the ejection of the products is effected in a different manner, and. it is to be understood that the invention also relates to such tables, the type of table described in this specification having been referred to solely with a view to facilitate the description of the invention.

The cleaned coal is thus collected in the hopper 4, the mixture to be re-cleaned in the hopper 5 and the shale at the end of the table at 6. For the automatic control of the operation of the dry cleaning table when the quantity and qual-' ity of the crude coal feed varies, it is necessary automatically to displace the blades which, in this case, are disposed at the separating line of the coal and mixture on the one hand and the sep- I arating line of the mixture and shale on the other hand.

For this purpose there are provided at the point where the cleaned coal is separated from the mixture to be re-cleaned two blades I and 8 which are integral and parallel to each other. These blades are pivoted on the fixed axle 9 and the heaviest part of the cleaned coal continuously caught between the two blades I and 8 flows on to a distributor I0 of any desired type, comprising for example an endless belt, which feeds part of the products caught between the blades I and 8 in a continuous manner and under constant charge on to the weighing instrument II, the surplus passing over the edge I2 by way of overflow into the hopper 4.

The weighing instrument substantially com prises a beam 13 freely oscillating on the knife edge I4 and having a small conveyor I5 for example of the band type continuously operated at a constant speed by an electric motor I6.

It will be seen that the conveyor I5 continuously receives a regular charge of the products collected between the blades I and 8, said regular charge then passing at the end of the conveyor into the hopper 4 for cleaned coal ina continuous manner. The conveyor driven at a constant speed is therefore always charged with the same amount by volume of said products and the inclination of the beam I3 corresponds at any moment accurately to the density of the product on the conveyor IS.

The beam I3 has an arm II which is located between two terminals I8 and I9 and according to the density of the products on the conveyor l5 either remains between or makes contact with one of the said terminals.

The blades I and 8 tend to turn in the direction of the arrow 28 under the action of the counterweight 2I but are retained by a cable 22 which is moved in or against the direction of the arrow 23 according to the direction of rotation of an electric motor 24 started up by means of. the electromagnetic relays 25. Between the cable 22 and the motor 24 a suitable reducing gear 26 is interposed.

Thus, when the arm I! of the weighing instrument II is placed between the terminals I8 and 19 the blades I and 8 are stationary. When the density of the products passing between the blades I and 8 increases the arm II approaches the terminal I9 and if the density is sufliciently increased makes contact therewith, thereby the electromagnetic relay is released and the motor 24 is started up in such direction as to pull the cable 22 in the direction of the arrow 23, so that the blades I, 8 are tilted in the direction of A and catch the products of smaller density. Then, when the density of the products passing between the blades I, 8 corresponds to that to which the device has originally been adjusted the arm II leaves the terminal I9 and the motor 24 stops. The function is the same when the density of the products passing between the blades I and 8 is reduced, in which case the terminal I3 comes into play and the motor 24 rotates in the reverse direction, so that the cable 22 is moved in a direction opposite to that of the arrow 23.

It is evident that the automatic control of a pneumatic cleaning plant must depend upon the density of the products. Since it is possible to adjust the device so that a slight variation of density will cause the arm II to make contact with the terminal H3 or 9, it will be obvious that by means of the device according to the invention the automatic control of the evacuation, at determined densities, of the product coming from dry cleaning tables can be effectively accomplished.

Instead of collecting all the products passing between the blades I and 8, it is possible to collect only a certain part of. the full amount of cleaned coal. In this case the device would possess a medium sensitiveness.

In order to provide a complete automatic control device for the example referred to, in which case there are three products obtained on the pneumatic cleaning table, it is sufficient to place between the hoppers 5 and ii a blade 21, pivoted at 28 and provided with a counterweight 29, the blade 21 being secured to the blade I by means of a link 30.

By its displacement along the ramp 3 of the table, the blade 21 varies the respective lengths of the zones through which the products pass to the respective hoppers 5 and 6, the heaviest products falling into the hopper 6 and the lighter products or mixtures falling into the hopper 5.

It is obvious that without leaving the scope of the invention a weighing mechanism ll of any desired type could be utilized, the electromagnetic relay being retained or not as desired, shoe in some cases the blades I and 8 could be directly operated by the weighing mechanism I I through suitable devices or through a servo motor of any type. Similarly, the conveyor I5 may be of any type and may consist of a band conveyor, a screw, a scraper conveyor, a feeder plate and so forth.

Also, the device may simply be an indicator giving an indication to the operator that adjustment is to be effected by hand. This device may consist, for instance, of any known system comprising two electric annunciators or sounding devices IB, 9 (Fig. 1*), each producing a sound different from the other, both devices being respectively actuated by the contact between II and I8 or between II and I9 according to the direction of, the displacement of the beam I3.

The invention is equally well applicable to cleaning tables with pneumatic action of any type.

Fig. 3 illustrates an automatic control device possessing the features of the invention, but wherein instead of weighing the products the density of which is of importance in a continuous manner, intermittent weighing operations are carried out in regular intervals. The two blades I and 8 are again operated by the same cable 22 which is pulled by means of the motor 24 started up by the electromagnetic relay 25. But in this case an electric device of time switch type for the contact maker causes the motor 24 to run for a certain period when it has been started up. This device may be, for instance, of the type of wellknown devices used in houses to light an electric lamp and to maintain said lamp lighted during a certain time after having actuated a contact stud. The said device, which would be located within the box 25 of the electro-magnetic relay, would be actuated, in the present case, by the contact between II and I8 or II and IS.

The weighing instrument I l is, in this case, of different construction. At one end of the two armed beam I3 two rigidly interconnected plates 3| and 32 are provided which are pivoted on an axle 33 fixed to bosses 34 secured to the forked end of the beam l3.

A drum 35 having a cavity 36 is continuously rotated by a small electric motor 31, so that the cavity 36 is periodically filled with products passing between the two blades I and 8 and normally falling into the hopper 4 for cleaned coal. As the drum 35 continues its rotation in the direction of the arrow 38 the contents of the cavity 36 is levelled by the blade 39, so that the cavity 36 always contains a constant volume of products which fall on the plate 3i through the hopper 40.

a slope at in order to actuate'a pawl I) mounted on an axle carried by one of the members 34.

This pawl is provided, at one end, with a slope d and, at the other end, with a fork e adapted to come in engagement with the rod 1 connecting the plates 3| and 32. A spring g tends to maintain the fork e in engagement with said rod 1.

As soon as the cam 42 actuates the pawl b,'the latter releases the rod 7'' and the upper plate, loaded with products, falls down in turning about the axle" 33 and empties itself, while the lower plate reaches the upper position; at this moment, the cam 42 releases the pawl b and the spring g causes the pawl 12 to come into engagement by means of its fork e with the rod 1" of the plates 3| and 32.

Any suitable means may be used for causing the rod 1 to automatically, stop in the vertical position, that is to prevent it from swinging past neutral. Likewise, the pawl 17 may be so formed that when it is moved to release the rod 1' it initiates rotation of said rod about the pivot 33 in the proper direction to start swinging movement of the plates 3| and 32. It will be seen that weighing operations are effected periodically and at as short intervals as desired and that according to the result of such operations the blades 1 and 8 either remain stationary or are displaced in the required direction.

What I claim is:

1. In an apparatus for separating materials, a vibrating table, a ramp at one side of the table having intersecting inwardly and downwardly inclined portions, a plurality of hoppers arranged at one side of the sill, shiftable means operating in conjunction with successive zones of the sill for catching a portion of the substances passing thereover, weighing means, means for taking a constant volume of the materials passing over said ramp and conveying it to said weighing means. means for operating said shiftable means, and means controlled by said weighing means for automatically causing the actuation of said last named means.

2. In an apparatus for classifying graded materia s, a vibrating table, a ramp atone side of the table having inwardly and downwardly inclined meetingportions, a plurality of receiving hoppers, means for automatically separating the graded materials according to their density as' inclined portions, a plurality of receiving hoppers, means for automatically separating the graded materials according to their density as they pass over the ramp and causing them to discharge into their respective hoppers, said means including a plurality of pivotally supported blades for directing material from said ramp into said hoppers, certain of said blades being arranged to form a chute, and automatic control means for said blades, said last named means including a balance adapted to receive discharge from the blades forming the chute, motor actuated means for shifting said; blades, and an electrical circuit controlled by said balance to operate the motor actuated means.

4. An apparatus for separating coal or like substances according totheir density, comprising in combination, a vibrating table, a plurality of hoppers arranged one after the other along the discharge edge of said table, and means for automatically distributing said substances from the table into said hoppers, said means including a weighing apparatus located at a lower elevation than the table, a classifying device positioned'adjacent the discharge edge of the table and adapted to catch a portion of said substances issuing from said edge and to direct said portion onto the weighing device while the bulk of said materials passes into a selected hopper, a reversible motor, means cooperating with the weighing apparatus for controlling the motor, and means for connecting the motor with said classifying device to alter its position with reference to the discharge edge of the table.

5. In an apparatus for automatically classifying materials of difierent density, the combination, including, a vibrating table, a ramp at one side of the table having downwardly inclined intersecting portions providing a plurality of successive zones over which the said materials are discharged, hoppers for receiving said discharged materials according to their density, and means for automatically distributing materials issuing from said ramp into the proper hoppers, said means comprising a device including a pair of spaced blades arranged in substantially parallel arrangement edgewise of the ramp and extending above and below the same, means for pivoting the blades beneath the ramp, a counter weight for moving said blades in one direction, weighing apparatus adapted to receive material passing between said spaced blades, and means acting in cooperation with said counter-weight for controlling the position of said spaced blades, said means being actuated by said weighing apparatus.

6. In an apparatus for automatically classifying materials of difierent density, the combination including a vibrating table, a ramp at one side of the table including downwardly inclined intersecting portions providing a plurality of successive zones'over which said materials are discharged, a plurality of hoppers for receiving said materials discharged from said ramp, said hoppers having adjacent walls in relatively contiguous relation, weighing apparatus arranged below the table; means for automatically distributing materials issuing from said ramp into the proper hoppers, said means comprising a device including a pair of spaced blades arranged in substantially parallel relation edgewise to the ramp and extending above and below the same, means for pivoting said spaced blades substantially at the junction of the relatively contiguous walls of one pair of hoppers, means for urging said blades in one direction, a single blade also disposed edgewise of the sill and pivotally mounted at the junction of one of said last mentioned hoppers and a third hopper, means for urging said single blade in one direction, a coupling connection between said single blade and said spaced blades, and means controlled by said weighing apparatus for simultaneously shifting said spaced blades and said single blade along the ramp.

7. In an apparatus for automatically classifying materials of different density, the combination including, a vibrating table, a ramp at one side of the table having downwardly inclined intersecting portions providing a plurality of zones over which the said materials are discharged, 2. plurality of hoppers adapted to receive materials discharged from said ramp, and means for automatically distributing materials issuing from said ramp into the proper hoppers, said means comprising a weighing apparatus, a chute in feeding relation to said weighing apparatus, a pair of spaced blades pivoted adjacent the mouth of said chute and disposed in edgewise relation to said ramp in the zone of the angle formed by said 'ntersecting portions of the ramp and adapted to be shifted to direct material into said chute and also into one or the other of said adjacent hoppers, means for normally urging said spaced blades in one direction, and means controlled by said weighing apparatus for actuating the said spaced plates in cooperation with said means for normally urging them in one direction, thereby to cause the discharge of material into one or the other of said receiving hoppers.

8. In an apparatus for automatically classifying materials of diiferent density, the combination including, a vibrating table, a ramp at one side of the table having inwardly and downwardly inclined intersecting edge portions providing a plurality of zones over which said materials are discharged, a plurality of adjacent hoppers adapted to receive materials discharged from the zones of said ramp, and means for automatically distributing materials issuing from the ramp into the selected hoppers, said means comprising a balanced beam weighing apparatus, a continuously driven belt conveyor in feeding relation to said weighing apparatus, a chute for discharging material onto said continuously driven belt conveyor, a pair of spaced blades shiftably mounted adjacent the mouth of said chute and disposed in edgewise relation to said ramp in the zone of the angle formed by said intersecting thereof, said blades being adapted to direct a portion of the material into said chute and the bulk of said material into one or the other of said adjacent hoppers, and means for shifting said blades relative to the ramp, said means comprising an electric motor operated element connected with said blades and a motor circuit including contacts adapted to be engaged and disengaged by a circuit making and breaking member carried by said balanced beam weighing apparatus.

9. In an apparatus for automatically classifying materials of different density, the combination including, a vibrating table, a ramp at one edge of the table having inwardly and downwardly inclined intersecting portions providing a plurality of zones over which the said materials are discharged, a plurality of hoppers adapted to receive materials discharged from said ramp, and means for automatically distributing materials issuing from said ramp into the selected hoppers, said means comprising a balanced beam weighing apparatus, a reversible electric motor, a circuit including said motor adapted to be opened and closed by the movement of said beam, and means for intermittently supplying a portion of the materials issued from said ramp to said beam of the weighing apparatus, said last named means comprising a pair of spaced blades shiftably mounted in edgewise relation to the ramp and between a pair of adjacent hoppers, an operating connection between said spaced blades and said reversible electric motor, a drum rotatable beneath said spaced blades and having a cavity adapted to receive material passing between said blades whereby as the drum rotates it will intermittently discharge increments of material passing between said blades onto said weighing apparatus.

10. In an apparatus for automatically controlling the classification of lumpy materials of different density, the combination including, a vibrating table, a ramp atone side of the table having downwardly inclined intersecting portions providing a plurality of successivev zones over which the said materials of different density are discharged, a plurality of hoppers adapted to receive materials discharged from said ramp; means for automatically distributing materials issuing from said ramp into the selected hopper, said means comprising a device shiftably mounted substantially in the zone of the angle formed by said inwardly and downwardly inclined intersecting portions of the ramp and including spaced blades whose outer portions are respectively adapted to direct materials issuing from said ramp into one or another of said hoppers, and the inner faces of said blades providing a passage for receiving a portion of the material issuing from said ramp, weight controlled contact means for receiving the portion of said material passing between the said blades, an electrical relay in circuit with said weight operated contact means, and a reversible electric motor operatively connected with said blades and in circuit with said relay.

11. In a separating apparatus, a plurality of hoppers, a vibrating table, a cascading edge at one side of the table and in feeding relation to said hoppers, and movable means responsive to the weight of materials of different density passing over said cascading edge to automatically change its position to direct materials of different density into separate hoppers.

12. In a separating apparatus, a plurality of hoppers, a vibrating table, a cascading edge at one side of the table and in feeding relation to said hoppers, and movable means cooperating with said edge to direct materials of different density into separate hoppers, said means having a portion for diverting and conducting a part of the materials passing over said edge away from said hoppers, a weight responsive apparatus for receiving said diverted portions of the materials, and means operated by said Weight responsive apparatus for changing the position of said movable means proportionally to the variation in density of the materials flowing over said edge.

DOMINIQUE SPINETTA. 

